…the beauty of a sunset, in all of its varieties and variations, is only enhanced the more you know about it.

Sunsets grab our eyes and our interest. They change colors, dominate the horizon, and sometimes we even see a flash of green or blue, if we're lucky. Sunsets even come with their own optical illusions. Cosmologist Ethan Siegel explains why sunsets are so magical.

You may not even realize it, but by time you’d see a sunset like the picture above, the Sun has already technically set, it’s only due to the fact that the atmosphere bends light that we’re still seeing it like this.

This is why, if you time a sunset, it will take longer than the expected 120 seconds to go from the moment it touches the horizon to the moment it dips below, even during the equinox at the equator, where it rises and sets as close to completely vertical to the horizon as possible. The Sun appears to linger due to the refraction of our atmosphere.

The explanation of this and other sunset phenomena comes with some awesome pictures at Starts With A Bang. Link